is there a relay?

Ive lost power to my speedometer and the fan motor is there a relay that gives them power when you turn the key or is it switched on some other way?

what type of truck do you have?

91 chevy scottsdale w/350 1/2 ton

When you say you lost power to the spedometer, you mean the light, right? And it's only the light for the spedometer? All of the dash lights should be on the same circuit, so I'd think burned out light there.

Have you checked the fuse that protects the fan already?

No i think he means his speedo doesn't work....check the "speedo" fuse in the panel under the dash. I think it is a 15 amp. These are electric speedometers in these trucks. 88 and up!

All fuses check good. I think the loss of power is from a relay under the hood. This problem was intermittant at first. I turned on the truck one day and started down the road when I noticed the speedometer and odometer weren't working, the abs light was on, and the fan for the heater/ac wouldn't come on. When I got to a stop sign, I shut off the truck, turned it back on, and everythink worked...for a day or two then same problem. This scenario happened a few times, but now it is constant. Any help would be appreciated. Thanks, Scott

You may want to buy a repair manual for your truck. It should have wiring diagrams and component locator charts.